Although applicable to any information sources and any information-output devices, the present invention and the problem forming the basis of it are explained with regard to audio sources and audio sinks, e.g. in an automobile.
In the case of a plurality of audio sources, e.g. audio devices such as a radio, CD player, navigation system, etc., one requires a mechanism which coordinates the release of audio-data output or audio-information output, e.g. music, voice output, video tone, etc., for each audio sink, e.g. loudspeakers, headphones, etc.
This mechanism must establish which audio source may execute an output when a plurality of audio sources want to send an audio output to an audio sink at the same time, e.g. when the audio sink is already busy when a new inquiry is subsequently made.
Known methods are primarily based on a priority control system, in which each audio source has a static priority. Audio sources having the same or higher priority interrupt each other, i.e. if an audio output of an audio source having, for example, a priority of 3 is made, this audio output is interrupted by an output of an audio source B having a priority of at least 3, but is not affected by an audio source C having a priority of less than 3.
The problem of a simple priority control is that more complex operations can no longer be carried out. In simple priority control, the order of audio-source interruption is linear, i.e. if audio source A interrupts audio source B and audio source B interrupts audio source C, then audio source A also interrupts audio source C. However, this is sometimes not desirable, since, in the example just mentioned, the intention may be for audio source A to indeed interrupt audio source B, but not interrupt audio source C.